Influence of egg warming during storage and hypercapnic incubation on egg characteristics, embryonic development, hatchability, and chick quality.

Negative effects of prolonged egg storage on hatchability and chick quality may be caused by changes in the embryo or in the egg characteristics, or by both. The aim of this experiment was to investigate whether prestorage incubation (PSI), frequent warming during storage (FW), or hypercapnic incubation (HI) during the first 5 d of incubation affect egg characteristics, embryonic development, hatchability, and chick quality. The experiment had a 2 × 2 × 2 randomized design: PSI (yes-no), FW (yes-no), and HI (yes-no). All eggs were stored for 15 d at 16°C and 75% RH. On the second day after oviposition, half of the eggs were incubated for 7 h (PSI). During storage, half of the eggs were warmed 6 times for 30 min in water at 37.8°C (FW). During the first 5 d of incubation, the CO(2) concentration in the incubator was maintained between 0.70 and 0.80% (HI) or increased from 0.05 to 0.20% (control). Prestorage incubation and FW increased the stage of embryonic development and the number of viable embryonic cells, but these treatments did not have a pronounced effect on egg characteristics, hatchability, or chick quality. Hypercapnic incubation decreased total albumen pH, which was measured at 18, 42, 66, and 90 h of incubation, and the percentage of eggs classified as infertile (Δ = 1.2%). In contrast, HI retarded embryonic development, decreased hatchability of fertile eggs by 1.3%, but did not affect chick quality. We conclude that both PSI and FW did not improve hatchability and chick quality, although the stage of embryonic development and the number of viable embryonic cells increased due to the treatments. Hypercapnic incubation decreased total albumen pH, which may be related to the increased number of embryos that continued their development at the onset of incubation. Because HI retarded further embryonic development and decreased hatchability, long-term stored embryos were probably sensitive to the CO(2) concentration of 0.70 to 0.80% between 48 and 72 h of incubation.